New footage has emerged of the violent removal of a passenger from a United Airlines flight earlier this week.

The passenger, Dr. David Dao, was forcibly removed on Sunday by Chicago Aviation Police at O’Hare Airport in Chicago after her refused to give up his seat to a UA employee.

The incident, which has sparked an angry backlash against United Airlines, began when company staff members announced to the Louisville, Kentucky bound flight from Chicago that the flight had been overbooked, and that four passengers already in their seats would have to give up their seats to accommodate UA employees.

The four UA employees were not on duty during the flight, but were slated for work on other UA flights out of Louisville the next day.

Rather than arrange alternative transportation for the four employees for the four-hour drive to Louisville, United Airlines instead chose to force off already boarded and seated passengers from the flight.

The four unlucky passengers would be required to leave the plane and wait for the next flight to Kentucky at 2:00 p.m. the next day – nearly a 24-hour delay.

Flight crew members initially offered volunteers a paltry $400 in vouchers as compensation for the inconvenience, and later upped the offer to $800 in vouchers and a motel room.

But when no passengers took the offer, rather than increase the bid and save the company from potential lawsuits and a public relations disaster, staff members instead chose to select four passengers for removal, calling in airport police to assist in their expulsion.

A young couple were the first two passengers forced off the plane.

The third, Dr. Dao, insisted he absolutely had to reach his destination that day, because he had patients who needed his care back home.

In the first viral video which was released this week, airport officers were seen ripping the screaming Dao from his seat before dragging him down the aisles and off the plane. An eyewitness told Fox News Dr. Dao was unconscious when he was dragged through the plane.

Images taken after he was removed show Dr. Dao’s face bloodied from injuries suffered during the removal.

Now a second video has emerged, showing the moments prior to Dr. Dao’s expulsion from the United Airlines plane.

Chicago Aviation Police officers can be seen urging Dr. Dao to voluntarily leave the plane, a request he refuses, insisting he must see his patients. Dr. Dao can also be heard stating he plans to sue United Airlines for the fiasco.

“I won’t go; I’m a physician, have to work tomorrow, 8:00,” said Dao.

When the police threatened to drag him out, Dao remained defiant.

“Well, you can drag me. I don’t go. I’m not going. I’m staying right here... I’d rather go to jail.”

While United Airlines has claimed Dr. Dao was “irate” and behaved in a “belligerent” manner, no evidence has yet emerged to back up the company’s argument. Passengers who witnessed the incident say the company’s claims are baseless.

“Thank you to all of the friends and friends of friends who shared my video of Dr. Dao before he was forcibly removed from our flight,” wrote Joya Griffin Cummings, a passenger who filmed the incident.

“For getting the word out that this passenger was no more ‘irate or belligerent’ than any weary passenger after a long day of travel would be.”

On Wednesday, attorneys for Dr. Dao filed an emergency bill of discovery in Chicago, a precursor to a full blown lawsuit for damages, against United Airlines and the operator of the airport – the City of Chicago.

A press conference by Dr. Dao’s attorneys has been scheduled for 10:00 Chicago time Thursday morning.